The present invention relates to a method of enhancing plant growth under artificial environmental conditions such as light intensity and CO.sub.2 concentration, and to an apparatus for performing such a method.
Various systems or methods of enhancing plant growth by controlling environmental conditions to thereby makes possible the industrial production of plants have been proposed.
In general, a plant produces organic substances in its leaves on the basis of the supplied water and carbon dioxide with the aid of light energy. A portion of the products are consumed by the plant to provide the energy necessary to maintain itself, and the remainder is delivered to and stored in its organs such as root and leaves, resulting in growth. It has been known that the growth of a given plant can be remarkably enhanced by controlling parameters such as light intensity, CO.sub.2 concentration and temperature etc. Therefore, land productivity may be improved and the factory production of plants becomes possible.
In the case of factory agricultural production, the utilization of solar energy might seem to be most efficient method in view of energy economy. However, since the amount of solar light depends upon seasonal conditions as well as weather conditions including temperature and humidity, plant behavior under such varying environmental conditions is very complicated, resulting in difficulties in planning plant production. Furthermore, in order to make environmental conditions other than light constant, a huge air-conditioning facility may be required, resulting in economical disadvantages.
In order to make periodic plant production realizable, it has been proposed to use, instead of solar energy, an artificial light source of a constant intensity. In this case, however, the required power becomes so large as to make such a plan impossible in view of economy, although other environmental conditions may be controlled relatively easily.